Expansion-mandrel.



A. JEPFBRYS. EXPANSION MANDREL.

APPLIOATION FILED JAN. l i909.

Patented Aug. 9, 1910.

MW INVENTOR 4 Tram/s ALBERT JEFFERYS, 0F PHILADELPHIA, PENNSYLVANIA.

EXPANSION-MANDREL.

Specification of Letters Patent.

Application filed. January 7, 1909.

966,449. Patented A11 9, 1910.

Serial N0. 471,064.

To all whom it may concern:

Be it known that I, ALBERT JErFnRYs, a citizen of the United States ofAmerica, residing at Philadelphia, in the county of Philadelphia andState of Pennsylvania, have invented certain new and useful Improvementsin ExpansionMandrels, of which the following is a specification.

My invention relates to improvements in expansion mandrels for use onmilling and grinding machines, lathes, planers, etc., designed to admitof expansion to fit different diameters of borings, etc., and has forits object the reduction of parts and an increase of simplicity andstrength over present inventions of its nature in use.

In the drawings Figure 1 is a side view of a mandrel with two bushings,one fully expanded and the other not yet expanded. Fig. 2 is a sectionalview on the line 2-42 of Fig. 1 lookingin the direction of the arrows.Fig. 3 is a similar section on the line 3-3 of Fig. 1. Fig. l is asection through the bushing of Fig. 3 on a plane dividing the chamber ofthe spring E thereof. Fig. 5 is a transverse section through the bushingshowing the chamber containing the pin F. Fig. 6 is a section similar tothat of Fig. I, through the same chamber as in Fig. 5 but at rightangles thereto.

I attain these objects by the construction shown and described in theattached drawsprings would serve to a full extent the end desired,namely that of keeping the extremities of the jaws in the sametangential plane, for in order to afford greater strength in some workand to provide better alinement, I prefer to use an alternatecombination of springs and locking pins as shown in Figs. 2 and 3 at F Fand E E. In Figs. 5 and 6 said locking pins are shown in more detail ona larger scale. One end of the pin F is permanently fixed in one of thejaws as at 7" while the other end slides freely in a recess f in theopposite jaw, and is limited in its outward movement by the key-pinThese locking pins and springs may be 0. various forms; I have shown.what I consider the simplest and most practical in my drawings.

My mandrel may be made triangular, pentagonal, any number of prefer thesquare form with slightly rounded corners as shown in Figs. 1 and 3 at Aand of such taper as will reduce to a minimum the chances of bushingslipping while in work.

Operation of mandrel is simple and will be obvious from a reference todrawings in which Gr Fig. 1 represents work to be turned, ground, etc.,and mandrel in position in bore before being driven in, and in same Fig.1 the mandrel is shown expanded round, square, hexagonal or with sides,but for simplicity I ings and fOHOWHIg SPBOifiCE i II n hi h in work Hand ready to be placed inmasimilar letters refer to similar parts in thehin several views. I am aware that certain non-essential A, Fig- 1, is atape ed 01 1 ided m n changes may be made without departing with aflexible segmental bushing B designed to slide thereon, said bushingconsisting of four angle jaws a. a a (1. held in position by alternatesprings E and locking pins F. The inner surfaces of the angle jaws ofbushing are made at an angle equal to that of taper of mandrel; theobject being to cause their outside surfaces to move and expand at alltimes during movement of tool parallel with axis of mandrel.

To secure an even expansion of mandrel and j to prevent one or more ofsections or angle jawsof bushing from advancing beyond its mates whenbeing placed in work, I provide on the longitudinal flat sides of saidangle jaws, grooves or channels cl cl Figs. 3 and 4:, in each of which alongitudinal spring E preferably of wire as shown is placed, the

which are suitably secured opposite ends of to opposite angle jaws. Insome work these from the scope of my invention, as for example in theshape of the mandrel, in the nature of the springs employed, and thelike. I wish it understood therefore that I contemplate all such changesas fall fairly within the scope of the appended claims.

WVhat I claim and desire to secure by Letters Patent is:-

1. In an expansion mandrel, the combination of a tapered spindle havingflattened sides, and a bushing thereon having a tapered bore shaped incross section to fit the spindle and composed of a plurality of segmentsforming when closed a cylindrical figure divided on planes radial to theaxis of the spindle, each adjacent pair of segments provided withregistering chambers in their parallel contiguous faces, and holdingmeans seated in said chambers, each holding means having one end securedto a segmental bushing being divided on planes radial to the axis ,mentsconnected across the by a spring extending substantially from other endsecured to the opposite segment, substantially as described.

An expansion mandrel comprising a tapered spindle of regular shape incross section, and a segmental bushing having a tapered bore to fit thespindle and when closed externally cylindrical in figure, with holdingmeans and steady pins connecting opposite pairs of segments,substantially as described.

5. An expansion mandrel comprising a tapered spindle of regular shape incross section, a segmental bushing with a tapered bore to fit saidspindle, with holding means one segment, and its opposite end secured tothe opposite segment, all substantially as described.

2. An expansion mandrel comprising a tapered spindle regular in crosssection, and having a tapered bore spindle; and when closed a surface,the segments of the spindle, and each adjacent pair of segments havingchambers formed in their juxtaposed faces, with holding means comprisingcompression springs lying partially in each chamber, and secured atopposite ends to the opposite segments, substantially as describe v 3.An expansion mandrel comprising a tapered spindle of regular shape incross section, a segmental bushing having a tapered bore to fitthe'spindle, and when closed externally cylindrical in ments beingdivided on planes radial to the axis of the spindle, and each pair ofsegline of separation the opposite segments, and steady pins extendingfrom one segment into another, substantially as described. 7

In testimony whereof I hereto afiix my signature in presence of twowitnesses.

ALBERT EFFERYS.

l/Vitnesses HERVEY J. SHERER.

end to end of the bushing, and with one of HEPNER F. VAN HORN.-

its ends secured to one segment and the

